# 不使用中间变量 和 a, b = b, a 方式完成变量的交换
"""
1.记录a,b的值
a = 1 b = 2
a = a + b
b = a - b
a = a - b
"""
a = 1
b = 2
print("交换前a=", a, "b=", b)
a = a + b
b = a - b
a = a - b
print("交换前a=", a, "b=", b)
